U.S. Route 20 over McLean Boulevard Interchange

IDOT – District 1

OBJECTIVE

Existing traffic in the area had grown to levels that exceeded the capacity of the intersection, causing long delays, and unsafe traffic backups on U.S. Route 20. The solution was a single point urban interchange.

PROJECT DESCRIPTION

HLR was hired by the Illinois Department of Transportation (IDOT) to provide preliminary engineering for the improvements to the interchange to alleviate traffic congestion and maximize the use of the existing highway right-of-way, working within the constraints of the urban setting. In addition to a reconfigured interchange, our team looked at interim improvements that could be built without removing the existing bridges.

In addition, HLR’s construction engineering team oversaw the improvements over the course of multiple construction seasons which included bridge demolition, construction of a three-span bridge, cast-in-place retaining walls, PCC and HMA pavement, guardrail, underground utilities, and four detention ponds along U.S. Route 20. McLean Boulevard was reconstructed with a hinged joint pavement and included new concrete curb/gutter, culverts, traffic signals, lighting, pavement markings, and seeding/sodding.

Throughout the project, public involvement activities included informational mailings to adjoining residents and business owners, informational meetings with a neighborhood association, and weekly construction updates.

Project challenges included extensive utility relocation coordination, piling redesign coordination due to unidentified soil conditions in pre-construction geotechnical reports, and disposal of creosoted timber piles and contaminated soils.

This project included close coordination with the following:

• City of Elgin
• Elgin Community College
• PACE
• Local businesses
• Elgin Fire Department

Our construction engineers led this project with a Complexity Factor of 0.035 to successful completion. We received ratings of “Excellent” for Construction Inspection.

Awards:

• IDOT’s 2007 Award for Exceptional Consulting Engineering Services for a Phase I Urban Highway

Scope of Work:

• Geometric design of alternate interchange types
• Traffic flow modeling
• Intersection/interchange design studies
• Preliminary bridge design (TS&L plan)
• Location drainage study
• Stormwater management analysis
• Storm sewer system
• Right-of-way plans
• Construction staging
• On-site construction observation
• Progress meetings
• Pay Estimate/Change Order/Authorization preparation
• Plan constructability reviews and redesign
• Material coordination
• Utility coordination
• Soil undercut determination and proof rolls
• ICORS/IDOT documentation and closeout